diff --git a/src/libslic3r/Algorithm/RegionExpansion.cpp b/src/libslic3r/Algorithm/RegionExpansion.cpp
index 83561fc83b..3846c47495 100644
--- a/src/libslic3r/Algorithm/RegionExpansion.cpp
+++ b/src/libslic3r/Algorithm/RegionExpansion.cpp
@@ -5,6 +5,8 @@
 #include <libslic3r/ClipperUtils.hpp>
 #include <libslic3r/Utils.hpp>
 
+#include <numeric>
+
 namespace Slic3r {
 namespace Algorithm {
 
diff --git a/src/libslic3r/ClipperZUtils.hpp b/src/libslic3r/ClipperZUtils.hpp
index d69b2e28a3..31f8228137 100644
--- a/src/libslic3r/ClipperZUtils.hpp
+++ b/src/libslic3r/ClipperZUtils.hpp
@@ -1,6 +1,7 @@
 #ifndef slic3r_ClipperZUtils_hpp_
 #define slic3r_ClipperZUtils_hpp_
 
+#include <numeric>
 #include <vector>
 
 #include <clipper/clipper_z.hpp>